mtXcontrol is an editor written in Processing to easily create image sequences for several output devices containing multicolor LED matrix. By now, the Rainbowduino controller and the Novation Launchpad are supported. Its generic API allows to add other in- and output devices easily. mtXcontrol Editor auto detects and connects to your device. Once connected, you can draw points, lines & rows in different colors, create multiple frames and manipulate them. Add, delete, move, fill, copy & paste of frames is supported. Play all frames by different speed, realtime update the device and save your work as image file. If supported (e.g. Rainbowduino), update the sequence on your device and run it standalone. One special feature is typing letters and numbers. Future versions aim to support multiple devices, different color depth and many more.